Record an unbuilt decision

Record an "unbuilt" decision

You are adding one entry to the project's deliberate-omissions ledger, UNBUILT.md, at the root of the current project. This is the record of things the project chose not to build, and why — the mirror image of a decision record.

Steps

1. Work out the entry.

   • If arguments were given, use them as the substance: $ARGUMENTS
   • Otherwise, summarise the decision that was just made in the conversation.
   • You need three things. Ask the user only for what is genuinely missing:
     • Left unbuilt — what is being deliberately not built, or the boundary.
     • Why — the one-line reason.
     • Revisit if — the condition that would reopen it (use "—" if none).

2. Read the existing ledger. Look for UNBUILT.md in the project root.

   • If it exists, read its full current contents first.
   • If it does not exist, create it with the header shown below.

3. Append the new entry — never overwrite.

   • Add your entry to the end of the file using an edit that inserts after the existing content (the Edit tool). Do not reconstruct the whole file from memory and write it back — that is how entries get dropped. If the file is too large to read in full, still only append; never rewrite it.
   • Preserve every existing entry exactly as-is: do not reorder, edit, or remove anything already there. If the file exists but has no header or looks malformed, still only append — never "repair" or rewrite existing content.
   • Title the entry with a short noun phrase and today's date (YYYY-MM-DD).

   Entry format:

   ## <short title> — <YYYY-MM-DD>
   **Left unbuilt:** <what is deliberately not being built, or the boundary>
   **Why:** <one-line reason>
   **Revisit if:** <condition that would reopen this, or "—">
   

   If you are creating the file, start it with this header, then the first entry:

   # Unbuilt
   
   Things this project deliberately does **not** do, and why — so they are not
   silently re-added later. Newest entries at the bottom.
   

4. Confirm. Tell the user, in one line, what you recorded. If the write fails (for example, a read-only folder), say clearly that the entry was not saved.

Rules

• If you cannot safely preserve the current contents, stop and say so rather than risk losing entries.
• Keep entries short — one decision per entry.
• Write only to UNBUILT.md at the project root (the top of the current working tree). Touch nothing else.